2 tablespoons butter
2 large leeks, sliced
4 cloves garlic, chopped
1/2 teaspoon ground coriander
1/2 pound new potatoes, sliced into thin batons or cubed
1 head frisee, chopped
1 head escarole, chopped
2 cups spinach, chopped
1 teaspoon kosher salt
1/2 teaspoon pepper
3 cups vegetable broth
Salt & pepper to taste
2 tablespoons cream (optional)